1. Field of the Invention
This invention relates to devices for protecting cable as it is pulled through a duct or conduit.
2. Description of Related Art
In those instances where cable or wires must be run through a concrete, plastic or metal duct, or a conduit or pipe, a device commonly referred to as a cable protector is often placed at the open end of the duct or conduit for the purpose of protecting the integrity of the cable as it is pulled into the duct or conduit. Indeed, the rough edge of a duct or conduit can often damage the cable, rendering it inoperative or useless. Generally, these cable protectors have comprised a rounded split piece of semi-rigid, semi-flexible material (such as plastic) of a uniform thickness which is folded over to form a tubular-like shape capable of fitting into the open end of the duct or conduit. These cable protectors are equipped with a smooth flanged end whose purpose is to protect the cable or wires from having contact with the end of the duct or conduit as the cable is pulled therethrough. A typical prior art cable protector of this type is known as the "Leaderguard" brand (types 345, 800, 225 and 400) manufactured by Virginia Plastics Company, Inc. of Roanoke, Va.
A major difficulty with the cable protectors which are presently in use is that, as the cable protector is folded over for placement into the duct or conduit, the flanged end of the protector turns inwardly and upwardly. That is, the more the cable protector is folded over to create a smaller tubular configuration, the more the flanged end turns inwardly and upwardly. If folded over enough, the flanged end would disappear completely. This creates the likely possibility of the cable protector being pulled into and lost inside of the duct or conduit as wires or cable are pulled therethrough.
In addition, since the present cable protectors are designed to be of a uniform thickness throughout, a centerline is created as the cable protector is folded over for insertion into a duct or conduit. This centerline is naturally stressed more than the other areas of the cable protector on each side of the centerline. Thus, the cable protector may fracture along the centerline rendering the cable protector useless. The creation of the centerline fold also prevents the cable protector from having the substantially tubular configuration of the duct or conduit in which it is placed. Thus, the cable protector may encounter some difficulty in being inserted into the duct or conduit.
Further problems encountered with the cable protectors currently in use is that the smooth polished outside surface of the cable protector may be scratched or cut due to a sharp edge or burr. This creates a potential point of fracture, particularly in cold or dry conditions. Also, current cable protectors are provided with a smooth polished inside surface. This smooth surface can create additional surface friction as cable is drawn therethrough, potentially causing damage to some insulations on the cable.